Method for conditioning wellbore fluids and sucker rod therefore

Abstract

Invention refers to a method for conditioning wellbore fluids and to a sucker rod to accomplish the method used in the field of petroleum production. The method the invention refers to involves fact that the injection of the conditioning fluids is done directly through the sucker rods, from the surface, concomitantly pumping (producing) the well, being possible that the conditioning fluid be distributed either in the producing tubing or in the wellbore, or even in the reservoir rock around the wellbore, concomitantly pumping the well. The sucker rod designed for the application of the method is made of steel and it has two sucker rod heads ( 1 ) which are tubular, welded to the ends of a tube ( 2 ) made of steel, thus forming a continuous tube through which a fluid can flow or an electric or optical cable can be pulled through, or set inside.

1. In combination: a sucker rod for a wellbore having a downhole pump and adapted to introduce a conditioning fluid during production pumping of a well, the sucker rod being assembled into a hollow pumping string and being made of steel, profiled and threaded at both ends, the sucker rod comprising two sucker rod heads that are tubular, welded to the ends of a tube made of steel, thus forming a continuous tube through which the conditioning fluid can flow and an electric or optical cable can be pulled through, or set inside, each head having an inner hole of cylindrical section from a top end of the sucker rod thread down to approximately the lower end of an upset bead of the head of the sucker rod, the cylindrical section being followed by a conical section and ending with another cylindrical section extending all the way through a welding zone of the head of the sucker rod, between the conical section and the cylindrical section there being provided a radius that works as a stress relief:
 a hollow rotor of a progressive-cavity pump, used to pump the well concomitantly with injecting conditioning fluids; and 
 electrical/optical cables passing through the string, the cables transmitting to the surface signals about properties of the wellbore fluids or pump status, signals generated by adequate transducers mounted on the sucker rod string or pump, or transmitting power from the surface to downhole electrical motors used to drive progressive-cavity-pump, screw or electrical-submersible pumps. 
 
   
   
     2. In combination:
 a hollow progressive-cavity-pump pumping string made of steel and comprising a progressive-cavity-pump rotor which is hollow, made of steel, assembled together with a train of hollow sucker rods, each sucker rod being made of steel, profiled and threaded at both ends and, having two sucker rod heads which are tubular, welded to the ends of a tube made of steel, thus forming a continuous tube connecting the surface to a wellbore through which a fluid can flow or an electric or optical cable can be pulled through or set inside; 
 means for injecting conditioning agents; and 
 electrical/optical cables passing through the string and including electrical cables that transmit to the surface the electrical signals about properties of the wellbore fluids or pump status, generated by adequate transducers mounted on the sucker rod string or pump itself, or that transmit power from the surface downhole to the downhole electrical motors used to drive progressive-cavity-pump, screw or electrical-submersible-pump pumps. 
 
   
   
     3. An oil-well system comprising:
 a production tubing in a wellbore extending from a surface to an oil production location; 
 a downhole pump along said tubing having a driven member displaceable to force wellbore fluids upwardly through said tubing; 
 a sucker rod string in said production tubing and comprised of a plurality of sucker rods connected end to end and connected to said member for driving same, each of said sucker rods having:
 respective heads at an upper end and a lower end, each head being formed with a threaded portion, followed by a constricted relief portion, followed by a shoulder, followed by a square cross section wrench portion, followed by a bead portion along an exterior of the respective head, and 
 a steel tube welded to each of the bead portions of the respective sucker rods, said heads internally being formed with cylindrical bores running from each end to the respective bead portion, a conically widening passage extending from the respective cylindrical bore toward said tube, and a cylindrical bore connecting each passed with said tube, said sucker rod string forming a clear passage from a top to a bottom thereof; 
 
 an injection valve at the bottom of said sucker rod string for discharge of a conditioning fluid into said wellbore fluids, into said wellbore and into structures around said wellbore; 
 an above-ground motor connected to said sucker rod string for displacing same to drive said member; and 
 a stuffing box and an inlet for supplying the conditioning fluid to said clear passage of said sucker rod string at said top thereof.